Hedera is phasing smart contract calls out of Atomic Batch Transactions, narrowing the feature toward native network operations while keeping standalone contract execution unchanged. The transition began in September with a six-month deprecation period and is expected to culminate in March 2027, when smart contract calls will no longer be accepted as inner transactions inside atomic batches.
According to Hedera’s official announcement, batches can currently contain no more than one smart contract call, and that call must appear as the final inner transaction. Any batch containing multiple contract calls, or positioning one before another inner transaction, is now rejected. Native token, account and consensus-service operations continue to function through atomic batching without this restriction.
Hedera Separates Native Batching From EVM Execution
Atomic batches are designed to combine multiple Hedera service transactions so that the group succeeds or fails together. The change does not remove that functionality. Hedera is instead separating native multi-transaction coordination from EVM contract composition, keeping atomic batches focused on the purpose originally defined by HIP-551.
Hedera says the underlying problem is architectural. Atomic Batch Transactions have no equivalent construct in the EVM, which prevents an embedded contract call from behaving exactly like the same call executed directly. Moving complex contract sequences into a single EVM execution frame gives developers more predictable ordering and execution semantics. Other networks are also revisiting transaction architecture, including Solana’s activation of Transaction V1 with a larger 4KB payload and the XRP Ledger’s upcoming Batch V1.1 transaction modes.
Developers affected by the change have several migration paths. Contract-dependent sequences can be moved entirely into smart contracts, while Hedera system contracts expose native token, account and scheduling functions from within EVM code. Workflows that do not require strict all-or-nothing execution can instead submit their operations sequentially. Standalone ContractCall transactions remain supported, so the deprecation does not reduce Hedera’s general smart contract functionality.
The adjustment illustrates a different approach from networks expanding individual contract capacity. Sonic, for example, recently doubled smart contract limits through its V2.2 execution upgrade. Hedera’s change is narrower: it alters where contract composition occurs rather than restricting how developers can use contracts across the network.
March 2027 Sets the Migration Deadline
Several properties of Atomic Batch Transactions remain unchanged during the transition, including their batch-key model, per-inner-transaction signatures and fees, native-operation atomicity and existing inner-transaction limit. Developers whose batches contain only native Hedera service operations do not need to modify their implementations, while mirror node, relay and consensus-node operators also require no action.
The change fits a broader blockchain engineering trend in which transaction formats are being redesigned around clearer execution boundaries. Ethereum and Base, for instance, have recently taken different approaches to native account-abstraction transaction structures, reflecting similar trade-offs between flexibility, compatibility and predictable execution.
The immediate milestone is March 2027, when Hedera expects the deprecation period to end and smart contract calls to be removed entirely from atomic batches. Teams currently combining contracts with batch transactions need to migrate that logic before the cutoff, while Hedera has said it will continue publishing reminders or adjustments during the transition. The practical result is a cleaner separation between native atomic batching and EVM-level composition rather than a reduction in the network’s standalone smart contract capabilities.
